Work machines such as tractors often include three point hitches for supporting and towing tools and implements, such as scrapers, blades, sprayers, and the like. For many applications, it is required or desired to have the ability for the towed tool or implement to closely follow a desired or predetermined path, such as an edge or boundary of an area to be scraped, for instance, the edge of a soil area next to a foundation, and where exceeding the boundary is undesirable or can possibly cause damage such as that which could result from contact between a scraper or blade and a foundation or wall. However, such three point hitches typically utilize draft links or arms for supporting and connecting to the lower portions of a tool or implement. The vertical position of the draft links is typically individually precisely controllable using fluid cylinders connected between the draft links and the work machine, but the connections allow generally free relative side to side movements of the draft links and the work machine over a relatively large amount of travel. Some sideward movement is required for hitches for construction and landscaping applications wherein the draft links are individually vertically movable by separate cylinders, so as to effect and facilitate sideward tilting of a scraper or blade. However, such side to side freedom of movement permitted by known hitches also allows swaying of the tool or implement and a resultant difficulty in maintaining precise side to side positioning thereof, for instance, for alignment with an edge or boundary of an area being worked by the tool or implement, such as soil area being landscaped adjacent to a foundation or wall.
To substantially limit or prevent such swaying, it is known to provide blocks which may be mounted in one or more alternative orientations or positions on a work machine or draft link, for preventing sway in one direction only. Such blocks are advantageous as they are relatively compact and allow close spacing between a wheel of a tractor and a draft link, but a disadvantage is that the blocks are required to be used in association with both of the draft links to prevent swaying in both sideward directions. Reference in this regard, Slosiarek et al. U.S. Pat. No. 3,847,228, issued Nov. 12, 1974 to Allis-Chalmers Manufacturing Company; and Teich U.S. Pat. No. 4,640,522, issued Feb. 3, 1987 to Deere & Company. As another disadvantage, a problem that can arise when using such blocks with a sidewardly tiltable hitch is that at least one of the draft links would have to be allowed to move sidewardly to accommodate sideward tilting movement, which would also allow at least some of the sideward swaying not desired for the reasons discussed above.
As an alternative, a variety of single arms and struts have been developed for connection between a structural element of a work machine and one of the draft links of a three point hitch, to provide bi-directional limitation of movements of the draft link, to thereby attempt to eliminate the need for devices such as blocks in association with each of the draft links. Reference in this regard, Kunze U.S. Pat. No. 4,203,613, issued May 20, 1980 to Jean Walterscheid GmbH; and Lang U.S. Pat. No. 4,265,464, issued May 5, 1981 to Deere & Company. However, devices such as these suffer from shortcomings including requirements for multiple pivotal connections, complexity, large size and space requirement, and relatively high cost.
In addition, it is desirable for the draft arms to be adjustable to accommodate category 1, 2 and 3 implements, requiring the draft arms to be capable of varied space therebetween. As a result, some draft arm constructions are joggled, resembling a flattened Z shape, or otherwise curved or non-linear. One consequence is that due to the offset between the ends of the of the non-linear draft arms, torsional loading can result when implements are subjected to side loading or other eccentric loading conditions. To prevent structural failure or bending under these conditions, the draft arms, associated fittings and work vehicle structures must be made more robust, adding weight, size and operating costs.
Further, depending upon the implement used, the work vehicle may also need to be provided rotational power, such as from a rotary motor. Alternately, counterweights may need to be connected to the work vehicle to provide additional ballast for increased traction for the wheels, depending upon the type of type of implement required. Typically, multiple counterweights are required for mounting to different locations of the structural elements of the work vehicle, since size is limited in combination with access requirements for the different moving components of the three point hitch or other components. In addition, the multiple counterweights require special mounting arrangements that are not interchangeable with other components to the work vehicle. Moreover, the counterweights do not contribute to the structural integrity of the structural elements of the work vehicle.
Thus, what is sought is a sway restricting apparatus that facilitates sideward tilting of a hitch, and overcomes one or more of the problems and/or disadvantages set forth above. Additionally, what is sought is a counterweight construction usable with the sway restricting apparatus that can be interchangeably mounted to structural elements of the work vehicle and further contributes to the structural integrity of the structural elements of the work vehicle.